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单一和多个指数模型

Single and Multiple Index Models
课程网址: http://videolectures.net/nipsworkshops2012_ravikumar_single/  
主讲教师: Pradeep Ravikumar
开课单位: 德克萨斯大学
开课时间: 2013-01-16
课程语种: 英语
中文简介:
高维环境下的统计估计,变量多于样本,在过去十年中一直是大量研究的焦点。现在我们很清楚,如果我们对模型空间施加适当的约束,在这种高维设置下,一致估计仍然是可能的。然而,当统计模型具有有限维参数形式时,这些结构约束通常更容易施加。将这些扩展到非参数设置的一种自然方法是使用半参数模型,并对半参数模型的参数组件施加这些结构约束。在本文中,我们考虑了单索引模型和多索引模型的半参数模型类。这里,回归函数假定为数据线性投影的单变量函数的总和。我们证明,我们可以将经典非参数回归(投影追踪回归和逆反)与基于凸优化的变分原理相结合,以解决在估计此类模型时出现的困难优化问题。特别地,我们证明了基于最大似然的标准方法是非凸的和脆弱的,但是我们可以使用Bregman发散来推导一个可计算的可处理的回火过程。我们演示了这种建模方法在视网膜建模应用程序中的实用性。
课程简介: Statistical estimation in the high-dimensional setting, with more variables than samples, has been the focus of considerable research over the last decade. It is now well understood that consistent estimation is still possible under such high-dimensional settings provided we impose suitable constraints on the model space. These structural constraints are however typically easier to impose when the statistical model has a finite-dimensional parametric form. A natural approach to extend these to the non-parametric setting is to work with semi-parametric models, and impose these structural constraints on the parametric component of the semi-parametric model. In this talk, we consider the semi-parametric model class of single and multiple index models. Here, the regression function is assumed to be a sum of univariate functions of linear projections of the data. We show that we can combine "classical nonparametrics" (projection pursuit regression and backfitting) with a "variational principle" based on convex optimization to address the difficult optimization problems arising in estimating such models. In particular, we show that the standard maximum-likelihood based approach is non-convex and brittle, but we can use Bregman divergences to derive a computationally tractable backfitting procedure. We demonstrate the utility of this modeling approach in a retinal modeling application.
关 键 词: 高维设置; 统计模型; 三维参数; 半参数模型; 指数模型
课程来源: 视频讲座网
最后编审: 2020-06-06:zyk
阅读次数: 61